Now it's the hosts' turn to indulge in a little Barca-esque keep-ball. Busquets puts a stop to that, though, with a good challenge.

47'

Here's Fabregas in midfield as Barcelona try to get something going. But the Milan pressing is superb again and Boateng picks up possession.

46'

Here comes Puyol - but Milan step in and Boateng is away down the right. He crosses, but that also comes to nought.

46'

Milan will get proceedings restarted. They play it long, but to no avail - that's straight through to Valdes.

45'

The second half is coming our way very shortly - the players are back out.

45'

And that's half-time - not a classic half. Milan have contained Barcelona superbly, but they will be desperate to score a goal of their own to take into the second leg at the Camp Nou.

45'

Downfield from Valdes, and thumped straight back upfield by Mexes. Abate comes forward and crosses - straight to the Barca 'keeper.

44'

Last couple of minutes of the half, and Barcelona are on the ball again. Alves crosses, and yet again Milan stand firm.

43'

Fabregas tumbles on the edge of the Milan box after an Iniesta pass. No free-kick, says referee Thomson.

42'

Xavi on the ball now: again, Milan are back in numbers, denying Barcelona space. Alba tries to get in on the left of the area, and Milan hammer that one away.

41'

Then Messi fouls Mexes. He doesn't like that decision. Meanwhile, Montolivo is down after a collision with Alba, but not for long.

40'

El Shaarawy runs at the Barca defence in an effort to change all that, but doesn't have enough support and is eventually crowded out.

39'

Heading towards the final five minutes of the first half, and no breakthrough in Milan so far.

38'

Muntari makes an overhead clearance, and is a bit winded by the fall from that one. He's back on his feet quickly, though.

38'

As it comes in, there is penalty area jostling and Puyol is penalised for a foul.

37'

Pedro saunters infield for Barcelona and links with Xavi. As Barca pass in midfield, Milan funnel back and have a wall of players between the visitors and the goal. That defence does its job again - but this time at the expense of a corner...

36'

Muntari, though, wins it back and when Boateng fizzes a ball into the area, El Shaarawy can't quite get a touch on it. A dangerous moment from Milan.

35'

Montolivo presides, and Barcelona clear.

34'

Milan can't get the ball off them - but now they do an El Shaarawy breaks. Busquets is then adjudged to have fouled Muntari - free-kick to Milan inside Barcelona's half.

33'

Intricacy from Barcelona down the left, and again obstinacy from Milan in response. But it's back with the visitors. Pass, pass, pass.

32'

Busquets starts a move that looks dangerous when the ball reaches Alves. But the flag is up, and that's that.

31'

Messi is wandering out to the right more and more. He plays it infield again, and this time Montolivo is the Milan man who has anticipated what's going on and clears.

30'

Alves reads Milan's plan well, cutting out a ball to the left and El Shaarawy.

30'

Lovely footwork by Messi on the right. He plays the ball in midfield, but the hosts slam the door shut again.

29'

There's no doubt that - as you would expect - the majority of the possession is with Barcelona. But there haven't been many chances so far, and the best of those has fallen to Milan's El Shaarawy.

29'

Messi embarks on one of his twinkle-toed runs, but Constant deals with it really well, standing his ground and then getting a good challenge in.

28'

Constant comes forward for Milan - and then bends his attempted pass down the left straight out of play.

27'

Pique wanders forward to find Iniesta. Xavi folats the ball towards Pedro, but it's over his head and is claimed by Abbiati.

26'

Fabregas produces a backheel inside the area, but Milan have read that one and they clear the danger.

25'

The ball is worked out to the left and Alba, then is switched back to the centre again. Then back to the left by Xavi. Then Alba again...

24'

Mexes gets the first yellow card of the night as a result, and Barcelona get the free-kick.

24'

He is dispossessed and forward comes Messi. He's tripped inside the Milan half by Mexes.

23'

Milan will be pretty pleased with the way they have played so far, and they find El Shaarawy on the left...

22'

Iniesta is on the edge of the box, but then a foul on Boateng, tracking back, brings any threat to an end and gives Milan a free-kick.

21'

Puyol produces some cool defending under pressure after a good ball down the left, and the visitors will bring it away.

21'

El Shaarawy scurries after another ball forward, but his scurrying is cut short by a linesman's flag.

21'

Then Fabregas gives it away, a wayward attempt to head it on in midfield easily intercepted.

20'

Zapata gives the ball away to Xavi... who then gives it away himself.

20'

He rolls the ball to Xavi, who belts one from long range - but Abbiati is right behind it.

20'

In comes a cross - Valdes catches and away comes Messi.

19'

Again, great purpose from Milan. They win it back, and are not giving Barca any time to settle into a midfield rhythm.

18'

But they're back again. Iniesta wins them a throw just inside Milan territory and down the left.

17'

The best opening of the game so far, then, has fallen to the hosts. Barcelona are back on the ball after that scare, moving through midfield until an attempted pass is cut out.

16'

...Boateng flicks the ball on, and it's only narrowly past the far post. But El Shaarawy had a wonderful chance there - will Milan get too many better ones?

16'

El Shaarawy races through into the Barcelona area on the left, but his touch is heavy and the ball is ushered behind by Barcelona. Corner...

15'

Muntari produces an extraordinary slice in midfield, sending the ball sailing high towards his own goal. Abbiati is there to catch and then Milan come forward...

14'

El Shaarawy hassles well in midfield, and now it's Barcelona's turn to be forced back.

13'

From it, good Barcelona pressing forces the hosts to go all the way back to goalkeeper Abbiati.

12'

Montolivo is brought down in midfield. It seems Milan have an advantage, but it's not played and they have to settle for a free-kick instead.

11'

Plenty of action already. Alves crosses from the right, but the flag is up as a defensive header drifts narrowly wide of the Milan goal.

10'

Pique gets there, but the ball is blocked again and then scrambled away - anywhere will do. Milan try to break, but it comes to nothing.

10'

Corner to Barcelona, which is cleared for another one.

10'

Lovely movement, but the cross is blocked. Messi than has a shot from the edge of the area, but it's blocked.

9'

Space for Alba on the left again, and he works it back to midfield before it goes back to him...

8'

Moments later, Fabregas is felled in midfield and Barca embark on another spell of keep-ball.

7'

Jordi Alba plays the ball forward down the left for Barcelona, and again Milan snap into the challenges and get it away.

7'

They lose the ball, however, and Zapata passes it back to Abbiati, who clears downfield.

6'

Boateng clips Messi inside the Milan half - free-kick to Barcelona.

6'

A decent effort, that one, and it was well-received by the Milan fans.

5'

The ball drops to Muntari just outside the area, and he belts a half-volley over the top.

4'

Back come Milan again, though, with Mexes playing the ball forward.

3'

Lovely interchanges on the edge of the area by Barca - Iniesta attempts to cross, but that threat is snuffed out.

3'

Already, there are signs that Milan will hassle and harry their opponents as much as possible, and they're getting plenty of encouragement from their fans.

2'

But the hosts win it back, and full-back Abate gallops down the right. He and the hosts would like a corner. Goal-kick, says Mr Thomson.

1'

Whistles from the home crowd as Barcelona keep possession, inside their own half.

1'

The visitors get the game under way - here we go ...

A sea of flags in the stands. Pendants being exchanged in the centre circle. Barcelona are in their yellow and orange change kit.

And here they come - to a huge reception. Tonight's referee, incidentally, is Scotland's Craig Thomson.

Five minutes remaining until kick-off - there's noise, there's high expectation, and the players are in the tunnel ready to emerge onto the pitch.

There's almost exactly half an hour until kick-off: stay with ESPN FC for all the drama from the Stadio Giuseppe Meazza.